The present invention relates to a method of preparing the intended organic compound to be obtained, as a more refined product from an organic reaction mixture.
It is well known that organic compounds to be used for photography and the like have various kinds of functional groups that exhibit intended photographic actions and functions, and they are obtained via steps of synthesis reaction. However, since the mixture thus obtained by way of these reactions generally contains a water-scarcely (sparingly) soluble compound and a water-easily soluble compound, it becomes important to prevent emulsion mixing and to efficiently carry out separation and purification. To separate the intended organic compound from the mixture, therefore, a variety of methods of obtaining the intended organic compound from the water-scarcely soluble compound while removing the water-easily soluble compound, have been proposed from the past.
As a typical method for removing such a water-easily soluble compound, a known method is separating the object, comprising steps of adding water to an organic reaction liquid, extracting a water-easily soluble substance in an organic reaction mixture into an aqueous phase, and then standing the liquid according to a separation method that utilizes the specific gravity difference between the phases, to thereby conduct phase separation into an organic phase and an aqueous phase, and then extracting the object from the organic phase (JP-A-4-230746, paragraphs 0052, 0061, etc.).
However, since the separation method by a specific gravity difference, which comprises standing a liquid, is low in separation efficiency, it causes such problems as that:
1) A water-easily soluble substance cannot be completely removed from an organic phase, which results in reduction in both the yield and quality of the object, and
2) Productivity of the object is low (it needs large-scale equipment and also requires much time).
Accordingly, an object of the present invention is to provide a method of highly precisely removing a water-easily soluble compound from an organic reaction mixture, and further obtaining the intended synthesized organic compound in a high yield with high quality.
Other and further objects, features, and advantages of the invention will appear more fully from the following description.